🌐 Rename "LCD Timeout" string

Marlin/src/lcd/language/language_de.h

   LSTR MSG_ADVANCE_K_E                    = _UxGT("Vorschubfaktor *");
   LSTR MSG_CONTRAST                       = _UxGT("LCD-Kontrast");
   LSTR MSG_BRIGHTNESS                     = _UxGT("LCD-Helligkeit");
-  LSTR MSG_LCD_BKL_TIMEOUT                = _UxGT("LCD-Ruhezustand (s)");
+  LSTR MSG_LCD_TIMEOUT_SEC                = _UxGT("LCD-Ruhezustand (s)");
   LSTR MSG_BRIGHTNESS_OFF                 = _UxGT("LCD ausschalten");
   LSTR MSG_STORE_EEPROM                   = _UxGT("Konfig. speichern");
   LSTR MSG_LOAD_EEPROM                    = _UxGT("Konfig. laden");

Marlin/src/lcd/language/language_en.h

   LSTR MSG_ADVANCE_K_E                    = _UxGT("Advance K *");
   LSTR MSG_CONTRAST                       = _UxGT("LCD Contrast");
   LSTR MSG_BRIGHTNESS                     = _UxGT("LCD Brightness");
-  LSTR MSG_LCD_BKL_TIMEOUT                = _UxGT("LCD Timeout (s)");
+  LSTR MSG_LCD_TIMEOUT_SEC                = _UxGT("LCD Timeout (s)");
   LSTR MSG_BRIGHTNESS_OFF                 = _UxGT("Backlight Off");
   LSTR MSG_STORE_EEPROM                   = _UxGT("Store Settings");
   LSTR MSG_LOAD_EEPROM                    = _UxGT("Load Settings");

Marlin/src/lcd/language/language_fr.h

   LSTR MSG_ADVANCE_K_E                    = _UxGT("Avance K *");
   LSTR MSG_BRIGHTNESS                     = _UxGT("Luminosité LCD");
   LSTR MSG_CONTRAST                       = _UxGT("Contraste LCD");
-  LSTR MSG_LCD_BKL_TIMEOUT                = _UxGT("Veille LCD (s)");
+  LSTR MSG_LCD_TIMEOUT_SEC                = _UxGT("Veille LCD (s)");
   LSTR MSG_BRIGHTNESS_OFF                 = _UxGT("Éteindre l'écran LCD");
   LSTR MSG_STORE_EEPROM                   = _UxGT("Enregistrer config.");
   LSTR MSG_LOAD_EEPROM                    = _UxGT("Charger config.");

Marlin/src/lcd/language/language_uk.h

     LSTR MSG_CONTRAST                       = _UxGT("Контраст");
     LSTR MSG_BRIGHTNESS                     = _UxGT("Яскравість");
   #endif
-  LSTR MSG_LCD_BKL_TIMEOUT                  = _UxGT("LCD Таймаут, с");
+  LSTR MSG_LCD_TIMEOUT_SEC                  = _UxGT("LCD Таймаут, с");
   LSTR MSG_BRIGHTNESS_OFF                   = _UxGT("Підсвітка вимк.");
   LSTR MSG_STORE_EEPROM                     = _UxGT("Зберегти в EEPROM");
   LSTR MSG_LOAD_EEPROM                      = _UxGT("Зчитати з EEPROM");

Marlin/src/lcd/menu/menu_configuration.cpp

   // Set display backlight / sleep timeout
   //
   #if LCD_BACKLIGHT_TIMEOUT && LCD_BKL_TIMEOUT_MIN < LCD_BKL_TIMEOUT_MAX
-    EDIT_ITEM(uint16_4, MSG_LCD_BKL_TIMEOUT, &ui.lcd_backlight_timeout, LCD_BKL_TIMEOUT_MIN, LCD_BKL_TIMEOUT_MAX, ui.refresh_backlight_timeout);
+    EDIT_ITEM(uint16_4, MSG_LCD_TIMEOUT_SEC, &ui.lcd_backlight_timeout, LCD_BKL_TIMEOUT_MIN, LCD_BKL_TIMEOUT_MAX, ui.refresh_backlight_timeout);
   #endif
 
   #if ENABLED(FWRETRACT)